Certain medical conditions or diseases require that patients intermittently inject a drug or therapeutic agent subcutaneously to maintain the medical condition or disease under control. Multiple daily injections (MDIs) may be required. One such medical condition is diabetes, for which insulin is injected to regulate blood glucose. An estimated twenty-six million people in the United States, or about 8% of the population, have diabetes. This percentage is expected to increase in the near-term as the population ages.
Certain patients are unlikely or unable to follow the drug regimen required to maintain their medical condition under control. Some patients are squeamish about injecting the drug themselves and others suffer adverse effects from repeated injections, such as bruising at the injection site.
Problems with existing mechanical insulin pens also discourage the patient from using them regularly. Mechanical insulin pens are bulky, requiring an extendable dial and a large working chamber, making the mechanical insulin pen itself large. Use of the mechanical insulin pen is also indiscreet: the patient must manually calculate the dosage, manually crank a large noisy visible dial to set the dosage, and then perform the injection with the large device. The mechanical components are also ill-suited to conversion to electronic operation.
To accommodate such patients, injection ports have been developed which only require that the patient puncture their skin every few days to install an injection port, rather than injecting with a needle into their skin numerous times a day. Injection ports employ a cannula inserted subcutaneously, and the patient injects the drug into the injection port adhering to their skin rather than directly into their cutaneous tissue.
Unfortunately, injection ports still require that the patient administer the therapeutic agent repeatedly throughout the day. Injection ports with dedicated reservoirs allowing bolus injection have been developed, but maintain a continuous flow path and run the risk of inadvertent bolus injection. Although these problems can be remedied with a dedicated electronic insulin pump, many patients are unwilling or unable to use a dedicated insulin pump due to the expense and complication.
It would be desirable to have an electronic injector that would overcome the above disadvantages.